1. Field of the Invention
This invention relates generally to preparation of food products for human consumption and relates particularly to the method and apparatus for partially preparing the food product in one location and completing the preparation in another location.
2. Description of the Prior Art
Heretofore food products such as meat, fowl and seafoods of various kinds have been cooked, deboned, placed in cans and sterilized using many methods which produce an end product substantially free from bacteria and palatable for human consumption. Most of the meat and fowl packing plants have been located in the same general vicinity as a slaughterhouse so that the process was carried out in essentially the same location from which the canned food product was shipped to the commercial markets. However, the seafood industry, and particularly the tuna industry, have captured the fish or raw product in an area substantially removed from the packing plant and therefore it has been necessary to store the fish in low temperature brine where it slowly freezes or add ice to the fish or blast freeze the fish to retard spoilage until the ships returned to their home port where the processing and canning has been done. Due to the long period of time between the actual catching of the fish and the processing thereof, a substantial portion has been unacceptable for human consumption due to spoilage, particularly when the fish have not been frozen immediately but have merely been placed into the hold of the ship until the hold was filled. The U.S. Government as represented by the Food and Drug Administration, has set rigid standards on the size, color, density and bacterial count of the fish which has further limited the number of acceptable fish delivered to the packing plants.
After the fish are delivered and accepted, some of such fish are retained in a frozen condition to be processed while the fishing fleet is at sea. Eventually all of the fish is thawed and then gilled and gutted by removing the head, tail, fins and internal organs of the fish after which the edible portions are steam cooked, deboned and canned with a known quantity of oil and broth and after the cans are sealed such cans are placed within a pressure retort where the temperature is raised to sterilize the contents of the cans. It has been determined that the mercury content of tuna fish varies with the size and variety and, therefore, it has been a common practice to blend the varieties to obtain a constant level of mercury.
In some cases, the fish are filleted at sea and only the loins are frozen so that the ships can stay out longer and bring in a higher quality product. However, filleted fish have greater surface area exposure per pound of fish so that dehydration by transpiration or leaching out of moisture has been a substantial problem. In an effort to reduce the problem, an anti-oxidant or glaze has been applied to the loins and such loins have been placed within film or other packages. However, the loins normally must be completely thawed before the covering material can be removed.
With regard to the tuna industry, four grades of tuna are acceptable, including solid pack which is solid pieces of prime loin of the tuna compressed together and usually packed with approximately 15% vegetable oil and broth or water; chunk light tuna in which at least 50% of the pieces are retained on a one-half inch screen and normally packed with approximately 15% vegetable oil and broth or water; flaked tuna which includes relatively small thin flakes which are compressed together and packed with oil, broth or water; and grated tuna which includes fine pieces packed with oil or water. Due to the fragile nature of the tuna, such tuna has been easily broken during handling so that excessive handling frequently results in tuna of a lower grade. Approximately 60% to 65% of the canned tuna sales in the United States are for chunk light tuna in oil.
In order to protect the highly labor oriented tuna industry in this country, a 35% duty has been placed on imported tuna which has been processed and packed in oil; a 6% duty has been placed on tuna which has been processed and packed in water; and little or no duty has been placed on raw fish or fish which has been processed but not packed in cans or other airtight containers.
With the progress in the tuna industry, the disposal of the unusable portions of the tuna has become a substantial problem due to U.S. Government controls as represented by the Environmental Protection Agency. Many efforts have been made to utilize the waste material, such as the production of fish fertilizer, fish meal, fish oil and the like; however, additional environmental problems such as obnoxious odors and an oily dirty waste effluent have accompanied the preparation of such byproducts. Therefore the disposal of the waste portions of the tuna has remained an increasing environmental problem.
Some examples of the prior art are the U.S. Pats., to Taylor, No. 1,864,285; Hopkinson, No. 2,110,801; Carruthers, No. 2,575,703; Lapeyre, No. 3,594,191; and Vogel, No. 3,677,775.